JPS6357282A - Thermal transfer material - Google Patents

Abstract

PURPOSE:To enable recording even onto a rough surface of paper, to improve the heat resistance and friction resistance, and to eliminate uneven inked surface, by forming a thermally fusible ink layer containing an oxidatively polymerizable compound onto a basic material. CONSTITUTION:An oxidatively polymerizable compound is a compound thermally fusible through heating of thermal head and hardened through oxidation polymerization upon completion of thermal transfer. It is a kind of resin being employed generally as vehicle for offset ink, and when it is applied onto a basic material with high viscosity, a surface protection layer mainly composed of wax is formed so as to prepare a thermal transfer material. Alternatively, three layer structure where an under layer mainly composed of wax is applied onto the basic material then an ink layer and an upper layer mainly composed of wax are applied may be prepared. In order to promote polymerization of the oxidatively polymerizable resin, dryer is placed preferably in the under layer which contacts with the basic material in the three layer structure or the surface side under layer or in the protection layer in the case of two layer structure having a protection layer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a thermal transfer ink sheet used for thermal transfer recording, and particularly to an ink sheet capable of recording on rough paper.

(Conventional technology) Fax machines thanks to the development of thermal heads.

The thermal transfer recording method has been adopted in office automation equipment such as word processors, typewriters, and printers.

It is known that a thermal transfer material (thermal transfer recording sheet) can be used in this method. This has a heat-fusible ink layer on a support, which is then layered with, for example, plain paper, and then heated by a thermal head to transfer the ink from the thermal transfer recording sheet to the plain paper to perform recording. . This method has the advantage of being able to record on plain paper.

That is, the heat generated from the thermal head passes through the support and melts the thermal transfer ink, thereby transferring the ink onto plain paper or the like. Conventionally, thermal transfer ink sheets are
The so-called hot-melt coating method involves coating a base film with a heat-melting ink whose main components are colorants such as pigments and dyes, waxes, and resins, etc., and the hot-melt coating method in which the ink dispersed in a solvent is applied by heating. It is made using methods such as lacquer coating.

Wax is often used in thermal transfer materials, but
Instead of this wax component, use JP-A-5! 1215891
No. Alkyl ester of phthalic acid, JP-A-57-20
No. 390 contains synthetic alloy wax, JP-A-59-212
No. 297 includes metal salts or esters of lanolin fatty acids;
JP-A-58-199195 newly discloses the use of a compound containing an atomic group called (NHCO). However, thermal transfer materials coated on a base material using a conventional heat-melting ink containing wax as a main component and heat-sensitive transfer materials coated on a base material using the waxes disclosed in the above-mentioned publications are paper with a rough surface. It is difficult to record well on paper, and even when recorded on paper with a very smooth surface, the printed matter is susceptible to heat and physical friction. Furthermore, these thermal transfer materials are unsatisfactory, such as when recording is performed by lowering the energy of the thermal head or by increasing the recording speed, as the printed characters become blurred or cannot be recorded at all. In addition, the heat-melting inks used to manufacture these thermal transfer materials have poor dispersion stability, which tends to cause sedimentation with wax and pigments during ink storage, and uneven coating during ink application. There are also many drawbacks in manufacturing thermal transfer materials, such as

(Problems to be solved by the invention) The present inventors have made extensive studies to improve the above drawbacks, and
By using a new material that was previously unknown, it is possible to record well even on paper with a rough surface.

We have succeeded in creating a thermal transfer material that has excellent heat resistance and abrasion resistance for recorded printed matter, allows excellent printing even at low thermal head energy, and has no uneven ink surface during coating.

Furthermore, they discovered that the ink used to make this transfer material has excellent dispersion stability, so the ink can be stored stably.

[Structure of the invention]

(Means for Solving the Problems) Namely, the present invention provides a thermal transfer material having a heat-fusible ink layer formed on a base material, wherein the heat-fusible ink contains an oxidation-polymerizable compound. It is related to
When recording with a thermal head using this transfer material, it is possible to record even on rough paper, and the heat resistance and abrasion resistance of the recorded material are significantly superior to conventional ones, and the energy of the thermal head is low. Also, it is possible to obtain a record with sufficient resolution (no thick recorded characters, no blurring, and no edges of characters are cut off), a record with no ink stains in areas other than the recorded area, and a plain record. Of course, when using paper, even when using rough paper, it is necessary to obtain uniformly recorded matter without ink leakage, to ensure that the applied ink surface is even, and that the ink is stable. It has the advantage of being able to be stored.

The oxidation-polymerizable compound according to the present invention is a compound that is heated by a thermal head to be thermally melted, thermally transferred, and then oxidatively polymerized and hardened.Resins that are generally used as vehicles for offset inks include linseed oil, linseed oil, eno oil, etc. , soybean oil, fish oil, or other beef oils.
Stand oil heated to about 90-300°C, or resin varnish made by melting rosin-modified phenolic resin, maleated oil, styrenated oil, dehydrated castor oil, etc., rosin,
Polymerized rosin.

Examples include natural or semi-synthetic resins such as hardened rosin, rosin ester, maleic acid resin, and synthetic resins such as phenolic resin and modified alkyd resin, but these resins include oleic acid, linoleic acid, and lylunic acid.

It contains unsaturated fatty acids such as rosin acid and their esters.

According to the present invention, inks can be produced using these oxidatively polymerizable resins by conventionally known general methods. The true melt ink applied by hot melt coating is made by heating and melting the above-mentioned oxidatively polymerizable resin and pigment, and if necessary, a small amount of wax or thermoplastic resin, and then kneading them.

When coating with a gravure printing machine, it is made by kneading oxidative polymerizable resin, pigment, and if necessary a small amount of wax, solvent, etc. in a ball mill or sand mill in the same way as conventional gravure ink. be able to. If necessary, a small amount of a plasticizer, surfactant-3 extender pigment, etc. may be added to the ink.

In addition, in the present invention, the transfer layer is provided by applying a hot-melt ink to a base material, but the application may include painting, printing, or any means that includes a painting or printing process.

When hot-melt ink is applied to a substrate by a method that includes a coating process, if the ink has strong tackiness depending on the type and content of the oxidative polymerizable resin contained in the ink, wax-based surfaces may A thermal transfer material can be made by forming a protective layer.

The protective layer at this time preferably has a coating thickness of 1 to 20 m.

The most preferable ink layer is 1 to 60 m.

Alternatively, a three-layer thermal transfer material may be used, in which a lower layer containing wax as a main component is coated on a base material in advance, and then an ink layer according to the present invention and an upper layer containing wax as a main component are applied.

To accelerate the polymerization reaction of oxidatively polymerizable resins.

Oxides and hydroxides of cobalt manganese, lead, zinc, etc.
Other inorganic salts and oleate, linoleate,
It is advisable to add small amounts of dryers such as organic acid salts such as lylunate, resinate, and naphthenate. However, since there is a risk of accelerating the curing reaction during ink production and application, it is preferable to keep the oxidative polymerizable resin and dryer separate until printing, and avoid contact with the three-layer base material mentioned above. It is preferable to insert a dryer into the lower layer or the upper layer on the surface side, or in the case of two layers with a protective layer, insert a dryer into the protective layer.

The base material used in the present invention is paper such as condenser paper, a heat-resistant film such as polyester or polyimide, or a film provided with a heat-resistant coating layer.

Hereinafter, the present invention will be explained in detail with reference to Examples.

All "parts" in the examples represent "parts by weight."

Example 1 The following ink composition was charged in a ball mill, and approximately 1
The mixture was kneaded for 0 hours to form an ink.

Ink composition Esterified product of linseed oil fatty acid and pentaerythritol 10 Ester wax (Hoechst wax S) 25 Carbon black 5 Cobalt naphthenate 0.05 Xylene
500 ethyl acetate
100 The obtained ink was printed on a 3.5 μm polyester film with a thickness of 3.8 μm using a gravure printing machine.
Solid printing was performed so that the thickness was .mu.m (dry). When this transfer sheet was printed on bond paper (rough paper, Beck smoothness: 3 seconds) using a normal thermal printer, good prints were obtained. Immediately after printing, 1 hour, 3 hours, and 1 day after printing, the friction resistance of the printed area was observed using a Gakushin type friction test, and the friction resistance was significantly inferior immediately after printing, but After 1 hour, it had very good abrasion resistance, and thereafter showed exactly the same excellent abrasion resistance until 1 day later. FIG. 1 shows the relationship between printing density and printing energy.

Example 2 The following composition was thoroughly kneaded using a three-roll heatable roll to prepare a hot-melt ink.

Esterified product of Chinese tung oil and glycerin 30 Montan wax (Montan wax manufactured by Hoechst) 50 Carbon blank 10 Ethylene-vinyl acetate copolymer 10 The obtained ink was coated on a 3.5 μm thick polyester film using a hot melt coater. It was coated so that the thickness was 4.0 μm. This transfer sheet was recorded on plain paper (Beck smoothness: 30 seconds) using a normal thermal printer, and the resulting print was subjected to a rub resistance test in the same manner as in Example 1. It has excellent abrasion resistance after a few days, and can be printed using less energy than conventional printers.

Example 3 Each of the following compositions was premixed into a 5 liter sand mill filled with 60% by volume of glass beads with an average particle size of 1.5 N, and was charged at a speed of 2 liters/min with a gear pump, and the sand mill was moved 10 m The mixture was rotated at a speed of 1/2 and kneading was repeated 5 times to make trial inks for a heat-fusible layer and a colored layer ink having the following compositions.

[Thermofusible layer ink-A]

Aqueous dispersion of carnauba wax (Note 1) (solid content 20%)
) 5 parts water-based acrylic resin (Okryl Ap-2 manufactured by Toyo Ink Manufacturing ■, solid content 2
7%) 0.5 part Cobalt naphthenate 0.01 part Isopropyl alcohol 50 parts (Note 1) Heat carnauba wax with a melting point of 83-84°C to 100°C, and add it little by little to 90°C hot water with vigorous stirring at room temperature. Aqueous dispersion obtained by cooling to.

[Ink for colored layer]

[Composition of yellow ink-11ml) 5 parts of esterified product of dehydrated castor oil fatty acid and glycerin Lionor Yellow GR (C, I manufactured by Toyo Ink Manufacturing @.

Pigment Yellow 12)
0.14 parts isopropyl alcohol
10 parts [Composition of red ink - 11kL2] Composition of yellow ink: Lionol Yellow 〇H was replaced with Lionol Resod B (C, I manufactured by Toyo Ink Seisakusho ■).

Plugment Red 38) 0.18 part was used.

[Composition of blue ink - Part 3] Composition of yellow ink: Lionol Blue KL (manufactured by Toyo Ink Manufacturing Co., Ltd. C, I) instead of Onor Yellow GR.

PIgmentBlue 15 3) 0.15 part was used.

[Composition of black ink - No. 4] Composition of yellow ink 21 parts of Mitsubishi Carbon MA-6000 was used instead of Onol Yellow GR.

Each of the obtained inks was applied as follows.

Using a gravure printing machine for 6-color printing, using Ink-A on a 6 μm polyester film? ? After solid printing the 'tR fusible layer to a thickness of 0.6 μm (when dry) using a gravure printing plate, yellow ink was applied.

Red ink, blue ink, and black ink were each printed at a constant size to a thickness of 0.8 μm (when dry). Furthermore, a heat-fusible layer was printed solidly thereon using Ink-A to a thickness of 1.8 μm (when dry).

This process is carried out continuously using a gravure printing machine, and
A heat-sensitive transfer material coated in different colors was obtained.

When this transfer sheet was recorded on bond paper using an ordinary color thermal printer, excellent color prints were obtained. The printed matter had sufficient abrasion resistance 30 minutes after printing.

〔Effect of the invention〕

The thermal transfer material of the present invention has a heat-melting ink layer containing an oxidation-polymerizable compound formed on the base material. Of course, even when using rough paper such as bond paper, it is possible to obtain a recorded matter with no areas where the ink is thick or missing evenly.

Even if the energy of the thermal head is low, it is possible to obtain a record with sufficient resolution (no thickening or blurring of the recorded characters, and no edges of the three letters are cut), and the resulting record has excellent abrasion resistance. There are advantages such as:

Further, the heat-melting ink used to produce the heat-sensitive transfer material according to the present invention has the advantage that it can be stored stably without separating during storage, and provides an even coated surface when coated.

Further, the heat-melting ink layer according to the present invention can be used not only in a thermal transfer method using a thermal head but also in a thermal transfer method such as electrical transfer.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between print density and applied energy. The vertical axis is the density of solid print using the Macbeth density needle, and the horizontal axis is the energy applied to the thermal head.
Shows the wattage per dot.

Claims (1)

[Claims] 1. A heat-sensitive transfer material comprising a heat-melt ink layer formed on a base material, characterized in that the heat-melt ink layer is a layer containing an oxidation polymerizable compound. . 2. In a thermal transfer material formed by laminating a plurality of layers including a heat-fusible ink layer on a base material, the heat-fusible ink layer is a layer containing an oxidative polymerizable compound, and at least one layer contains an oxidative polymerization accelerator. A heat-sensitive transfer material characterized by having a layer containing.